Ocular enhancement in Sturge-Weber syndrome.

We first want to congratulate the authors and the AJNR for the interesting case in “The Association between Tuberous Sclerosis and Insulinoma” (1). In this age of molecular genetics, these unusual cases have been shown to lead to major discoveries, as exemplified by the cloning of the neurofibromatosis type 1 gene. In the “Discussion,” the authors state, “Although multiple endocrine neoplasia [MEN] type II has been linked to chromosome 10, the genetic linkage of multiple endocrine neoplasia type I has not yet been delineated.” We would like to point out that the MEN2 gene was cloned in 1993 (2) and that the MEN1 gene was mapped to chromosomal region 11q13 in 1988 (3). Two tuberous sclerosis genes have been mapped, one to 9q (TSC1) and the other to 16p (TSC2), and the TSC2 gene was cloned in 1993 (4). The case could be related to either one of them. To date, more than 80 MEN1 families have been genotyped and no genetic heterogeneity has been detected (5), so the authors’ suggestion that MEN1 might be linked to chromosome 9 (tuberous sclerosis type 1 gene) is unlikely, although the possible relationship between tuberous sclerosis and MEN1 at the molecular level cannot be denied, but can be ascertained only after the genes are cloned and analyzed. However, it would be very interesting to carry out cytogenetic studies on this patient, because any karyotypic abnormality that might involve chromosomes 9, 16, or 11 will greatly contribute to the cloning of the tuberous sclerosis type 1 gene in 9q and the MEN1 gene in 11q13.